Gas pumps and compressors of the liquid ring type



Nov. 25, 1958 R. L. DARDELET I 2,861,736

GAS PUMPS AND COMPRESSORS OF THE LIQUID RING TYPE Filed Nov. 28, 1,955 2 Sheets-Sheet 1 ,ZIIZJU GDW .L. Darcie Let Nov. 251958 R'. L. bARD LET 2,861,736

GAS PUMPS AND COMPRESSORS OF THE LIQUID RING TYPE Filed Nov. 28, 1955. 2 Sheets-Sheet 2 E! 6 f X! H 4 a 24a 1 .fil) .DandeLez;

GAS PUMPS AND COMPRESSORS OF THE LIQUID RING TYPE This invention relates to gas pumps and compressors of the liquid ring type.

Efforts have always been directed to designing these pumps so as to give the best possible economic results, particularly by raising their output, through the increase of the useful axial dimension (useful length) of the rotor without anyincrease in the diameter of the rotor.

It has been found that when the ratio between the useful length and the diameter of the rotor exceeds a certain value, troubles occur in operation which reduce output in an amount which is all the greater as the compression ratio is higher. The limit value of'this ratio has been estimated at 40%.

This drawback has already been obviated by a partitioning of the pump body and rotor, perpendicular to the rotor axis, the partition or partitions of the rotor extending from the outside periphery to the inside periphery which delimits the circular cavity for the stationary distributor of the pump.

This partitioning generally gives good results but, ow ing to the fact that it extends up to the distributor, it limits the cross-section of the ports through which gas and water pass. This cross-section is very often fairly small and if it has not been properly machined, it may have to be enlarged by hand, which is a lengthy and delicate task.

Moreover, as the liquid ring is separated into clearcut sections by the said partitioning, it may become unbalanced, so that in certain cases gases may not be completely expelled from some of the compartments formed by the partitions.

The present invention enables these drawbacks to be obviated and the improvements it covers are characterized by the fact that the partitioning of the rotor, to which States Patent axially;

7 Fig. 4 is an axial cross-sectionof a pump similar t the previous one but with partitioned stator;

Fig. 5 is an axial cross-section of a liquid ring pump with overhanging rotor, improved according to the invention; F 1

Finally, Fig. 6 is an axial cross-section of a liquid ring pump with symmetrical rotor and stator, improved according to the invention.

a partitioning of the pump body corresponds, extends from the periphery of the said rotor but does not reach the distributor housing. It stops at a certain distance from the inside periphery of the rotor.

In a preferred embodiment of the invention the radial length of the partition (or of each partition) of the rotor is comprised between 0.1 and 0.25 of the rotor diameter.

The inside edge of the rotor partition or of each rotor partition is sharp or rounded.

Thanks to the invention, construction. of the pump is simplified, since it is no longer necessary to ensure strict observance of precise dimensions of the ports of the distributor or to finish them by hand.

In addition, the whole cross-section of the said ports is thus available. The liquid ring forms a perfect seal at the base (distributor) and all gases are expelled.

Other features and characteristics of the invention appear in the following description which relates on the one hand to the known art in the liquid ring pumps, and, on the other hand, to two specimen embodiments of a liquid ring pump improved according to the invention, said embodiments being given merely by way of illustration and shown diagrammatically in the accompanying drawing, in which:

The pump shown in Fig. l is of a type known in France as early as 1929, comprising a rotor 1 keyed on a shaft 2 and rotating in a lobed body or stator 3. The rotor 1 and the lobes of the stator 3 are divided, at right angles to the shaft 2, by partitions 4 and 5 respectively, so arranged as to be in line with each other. 7

The useful length of the rotor of this pump is equal to the sum of the lengths AB-l-CD and the ratio of this useful length to the outside diameter of the rotor is approximately-%. p r 7 Usually, lengths ABand CD are substantially equal.

Each half rotor is associated with a distributor 6 with the usual distribution ports. To' increase output by an eflicient lengthening of the rotor, while avoiding the troubles mentioned above, it is necessary to fit additional transversal partitions in each half of the rotor and stator, but in this case, the partitions (which, ashitherto designed, have extended to the inside periphery of the rotor) reduce the cross-section of the distributor ports and may unbalance the liquid ring, etc.

To simplify construction of the liquid ring pumps and make them more useful in practice, pumps with overhanging rotor as shown in Fig. 2, have also been designed.

In these embodiments, the rotor 11, working in conjunction with the stator 13, is mounted on the end of the shaft 12 and the useful length of the rotor is equal to the length EF. Here, the ratio of the useful length to the diameter is 40%, the piunp being considered as being half that shown in Fig. 1.

In this type of pump, if an increase of flow is sought (see Fig. 3) by increasing the useful length of the rotor 11a (working in conjunction with the stator 13a) to the length E 1 the same operating ditficulties as those described above are encountered. According to a wellknown technique, these difliculties can be overcome by partitioning of the rotor 11a and the stator 13a, transversely to the axis of the rotor, but this entails the drawback of the reduction of the cross-section of the distribution ports with the risk of the liquid ring becoming unbalanced.

In order to improve the output of a pump with an extended rotor of the type shown in Fig. 3, a partition 15 on the stator 13a only, as shown in Fig. 4, has been proposed.

Such a pump already gives better results than the pump in Fig. 3.

According to the invention, by providing the extended rotor (see Figs. 5 and 6) of a liquid ring pump with partitions transversal to the axis of said rotor combined with transversal partitions in the stator, the said rotor partitions starting from the outside periphery of the rotor but stopping at a certain distance from the inside periphery of the said rotor (and therefore at a certain distance from the distributor), the results obtained are at Patented Nov. 25, 1 958 3 least the same as; or even better than those obtained with the known pump shown in Fig. 1'.

This not only eliminates the operating troubles encountered when the rotor length is increased beyond a maximum ratio between the-1'1 efiil length of the rotor arid its diameter, but dirers iti'onal advantages.

A first adva'fitage in connectitin with operatioh; is that as the liquid ring is no longer divided into distinct sections (as in the known partitioned pumps), it adheres to the base (in the area near the distributor) thus ensuring complete exhaustion of the gas.

Another advantage is that it is possible to profit by whole useful cross-section of the distribution ports because the rotor partition' which extends only to a certain distance from the distributor, no longer covers the said port's. v r t V Finally; a third advantage, in connection with construction, is that it is not necessary to design the distribtition ports with the same accuracy as in the past where it was often necessary to enlarge the available. cross section of the rotor distributing ports by lengthy and iriinute hand work. p

Fig. 5 shows a' pump with overha-nging extended rotor 11a, Or'i the rotor and 'combinedlwith the transversal stator partition 15,- is a partition 7 extending from the outside periphery P of the r'otor to a certain distance from the inside periphery p of the said rotor.

The inside edge 5 ert e partition is advantageously sharp or rounded whichdac'il i'tate's the division o fth'e liquid ring during its centrifugal displacement and its" ad herence to the base during its centripetal displacement. It goes withoutsaying that in a liquid ring pump with a still more extended rotor; the number of partitions 15 and 7 will be increased.

Fig. 6 shows a liquid ring pump ofthe symmetrical type with a greatly extended rotor, improved according to the invention. v 7 h g In thisc'a'se; the stator 23 comprises three partitions 15, 15 and transyersal to therot'or axis, while the rotor 21 which is keyed on the shaft 22, comprises three stator partitions 15, 15 and 25, the two partitions 17 (as in the pump shown in Fig. 5) extending only to a certain distance from the two symmetrical distributors 6, while the partition 24 is integral with the hub 24a of the rotor. Here again, several paired partitions 15, 17 could be provided in each half of the pump according to the useful length of each half of the rotor.

The invention also applies to liquid ring pumps comprising one or several rotors of the type shown in Fig. 2 distributed along the shaft.

It goes without saying that the specimen embodiments of the improvements described above and shown in the accompanying drawing have been given merely by way of illustration and are in no way restrictive, and that detail changes can be made therein.

What I claim is:

I. 1. In aliquid ring pump in combination a lobed stator with at least one partition, a rotor rotatable in the said stator and having at least one partition, both partitions being arranged in' a same plane perpendicular to the rotor axis and the rotor partition having an external edge 10- dated substantially at the periphery of said rotor, and a stationary distributor which is surrounded by the said rotor, the rotor 13 'tition has a free inside edge which stops a certain distance from the inside periphery of said rotoij'fso as to be located at a certain distance from said distributor. I t h I 2; Pump as claimed in claim 1, wherein the radial length of the rotor partition is greater than 0.1 and shorter than 0.25 of the diameter of the rotor.

3. Pump as'claimed in" claim 1, wherein the inside free end of the rotor partition is knife-edged towards the retor axis.

References Cited in the tile of this patent UNITED STATES PATENTS 2,672,276 Adams Mar. 16, 1954 

